Aptitude - Time and Work - Discussion
Discussion Forum : Time and Work - General Questions (Q.No. 1)
1.
A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the fraction of the work that is left is :
Answer: Option
Explanation:
| A's 1 day's work = | 1 | ; |
| 15 |
| B's 1 day's work = | 1 | ; |
| 20 |
| (A + B)'s 1 day's work = |  |
1 | + | 1 |  |
= | 7 | . |
| 15 | 20 | 60 |
| (A + B)'s 4 day's work = | |
7 | x 4 | |
= | 7 | . |
| 60 | 15 |
| Therefore, Remaining work = | |
1 - | 7 | |
= | 8 | . |
| 15 | 15 |
Discussion:
344 comments Page 1 of 35.
Poorni said:
1 decade ago
Why (1 - 7/15)?
Deepa said:
1 decade ago
Can you explain how 7/60 came?
(2)
Appu said:
1 decade ago
@Deepa
(1/50+1/20) = (20+15)/300 //This get by cross multiplication.
= 35/300
= 7/60.
I think your doubt is clear now.
(1/50+1/20) = (20+15)/300 //This get by cross multiplication.
= 35/300
= 7/60.
I think your doubt is clear now.
(1)
Sundar said:
1 decade ago
@Poorni:
The total work = 1;
Work done by A and B in 4 days = 7/15.
Therefore, the pending work = 1 - 7/15 = 0.533333333... (or) 8/15.
Hope this help you. Have a nice day!
The total work = 1;
Work done by A and B in 4 days = 7/15.
Therefore, the pending work = 1 - 7/15 = 0.533333333... (or) 8/15.
Hope this help you. Have a nice day!
(1)
Beer ibrahim said:
1 decade ago
Why (1-7/15) is applied ?
(1)
Sundar said:
1 decade ago
@Beer Ibrahim
Q: Why (1-7/15) is applied ?
Ans: To calculate the work remaining. Work remaining = 8/15.
Note: From the above answer, we can say 15/8 days required to
complete the remaining work by A and B.
Hope this will help you. Have nice day!
Q: Why (1-7/15) is applied ?
Ans: To calculate the work remaining. Work remaining = 8/15.
Note: From the above answer, we can say 15/8 days required to
complete the remaining work by A and B.
Hope this will help you. Have nice day!
(1)
Mohideen said:
1 decade ago
@sundar.
Good explanation.
Good explanation.
Pravin Hambire said:
1 decade ago
Can you explain how 7/60 came?
Sunny guleria said:
1 decade ago
We have to calculate the remaining work after 4 dayz ,so why we subtract 1 dayz work from 4 day work? plz clear the question.
PRAKASH said:
1 decade ago
For A:-
15 days for 1 job
in 1 day 1/15 (part of the one job)
for B:-
20 days for 1 job
in 1 day 1/20 (part of the one job)
FOR BOTH IN ONE DAY:-
1/15+1/20=7/60
FOR BOTH IN 4 DAYS:-
(7/60)*4=7/15(THEY HAVE DONE)
THE REST PART OF THE JOB IS:-
1-(7/15)=8/15 (ANS)
15 days for 1 job
in 1 day 1/15 (part of the one job)
for B:-
20 days for 1 job
in 1 day 1/20 (part of the one job)
FOR BOTH IN ONE DAY:-
1/15+1/20=7/60
FOR BOTH IN 4 DAYS:-
(7/60)*4=7/15(THEY HAVE DONE)
THE REST PART OF THE JOB IS:-
1-(7/15)=8/15 (ANS)
(1)
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